230E 1985 gearbox won't shift

Post by **gez110** » Wed 22 Mar, 2017 9:39 pm

Hey guys,

I've recently bought my first Mercedes, a 1985 W123 230E. It came with a stack of service history but a gearbox that selects drive and reverse fine but won't shift up.

So far I've done the following

I've checked if the modulator valve holds a vacuum, it drops from around 15 down to zero in around 60 seconds, I believe this is normal?
I've disconnected the kick down switch, no difference
I've replaced a cracked breather hose that the gearbox vac line connects too, no difference

Other stuff I know

The previous owner had a local garage check the gearbox, they changed the oil and filter and reported metal swarf in the oil and therefore recommended replacement.
The central locking system has a massive leak, I'm in the process of checking this.

So, any ideas, recommendations on what to try next?

Cheers

Steve

Post by **Tony From West Oz** » Thu 23 Mar, 2017 12:16 am

How far did you rev the engine during your test drive. Take it to red line. Does it shift now? If so you may have a lack of vacuum getting to the modulator or a faulty modulator.
Does your central locking work properly? Is the brake booster working properly (depress brake pedal several times until the pedal gets hard. Then, while pressing the brake pedal, start the engine. The brake pedal should drop noticeably as vacuum builds up.
Note: if the vacuum take off from the main vacuum line gets blocked, you will experience vacuum related issues. Remove the vacuum spider from the vacuum take off nipple, drill out the nipple on the vacuum take off and reconnect it to the vacuum spider. If it was blocked, this should fix most of your vacuum issues.

Post by **gez110** » Thu 23 Mar, 2017 9:46 pm

Thanks for the reply.

I took it to the redline tonight, it didn't change gear, my kick down switch is disconnected, not sure if this could effect it?

Brake booster is working fine, I carried out the test, the pedal dropped once the engine was started.

Are you able to post a picture showing the location of the vacuum take off nipple?

Cheers

Steve

Post by **Tony From West Oz** » Fri 24 Mar, 2017 1:03 am

If it won't shift up at red line then I believe that there is something wrong inside the box.
Does your car have an "economy" gauge? That is actually a vacuum gauge and will show you the vacuum that the engine produces in the inlet manifold. At idle, or deceleration, the needle should be hard over to the left. At full acceleration it may be less than half way across the gauge.
The vacuum off-take is on the main vacuum line from the inlet manifold (or vacuum pump on diesel engine W123s) about 400mm from the brake booster. If the 'Economy' gauge works properly then you don't have an issue with the vacuum off-take.

Post by **gez110** » Fri 24 Mar, 2017 8:00 pm

Tony From West Oz wrote:If it won't shift up at red line then I believe that there is something wrong inside the box.
Does your car have an "economy" gauge? That is actually a vacuum gauge and will show you the vacuum that the engine produces in the inlet manifold. At idle, or deceleration, the needle should be hard over to the left. At full acceleration it may be less than half way across the gauge.
The vacuum off-take is on the main vacuum line from the inlet manifold (or vacuum pump on diesel engine W123s) about 400mm from the brake booster. If the 'Economy' gauge works properly then you don't have an issue with the vacuum off-take.

Bugger, the economy gauge is working as you describe. Time for a replacement box! Chris from MB spares reckons they have one. I'm waiting for a quote for shipping as I live in Tassie.

Really grateful for your help,

Cheers

Steve

Post by **gez110** » Tue 13 Jun, 2017 1:28 pm

Quick update. I managed to source a replacement gear box from Chris at MB spares. She's up and running now, really please. Thanks to every one who offered advice.

Post by **Tony From West Oz** » Tue 13 Jun, 2017 3:41 pm

Great, now to enjoy how the car should run.
Did you fix the vacuum leaks in the CL system?

Post by **gez110** » Tue 13 Jun, 2017 9:38 pm

Tony From West Oz wrote:Great, now to enjoy how the car should run.
Did you fix the vacuum leaks in the CL system?

Almost! I still have some small leaks which I'll aim to fix over the coming weeks :-)

Post by **AMG** » Tue 13 Jun, 2017 9:56 pm

part of the fun in owning a classic - always a never-ending source of new things to fix / maintain

:occasion5:

Post by **mathuisella** » Wed 14 Jun, 2017 1:42 pm

AMG wrote:part of the fun in owning a classic - always a never-ending source of new things to fix / maintain :occasion5:

watch this... it's totally related ( must watch it all )

https://www.youtube.com/watch?v=0ZvBwqemoLg

Post by **gez110** » Tue 20 Jun, 2017 7:25 pm

Haha, great video

230E 1985 gearbox won't shift

230E 1985 gearbox won't shift

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Re: 230E 1985 gearbox won't shift

Re: 230E 1985 gearbox won't shift

Re: 230E 1985 gearbox won't shift

Re: 230E 1985 gearbox won't shift

Re: 230E 1985 gearbox won't shift

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